Tissue-removing catheter, tissue-removing element, and method of making same

Abstract

A tissue-removing catheter includes a tissue-removing element operably connected to a drive shaft for rotation of the tissue-removing element about an axis of rotation in a cutting direction. The tissue-removing element is an integrally formed, one-piece body and has an annular tissue-removing head at the distal end of a tissue-removing element body. In some embodiments, primary tissue-removing components include an integrally formed cutting tooth and inner shearing member and are spaced angularly around the tissue-removing blade. Secondary tissue-removing components include cutting teeth and are interposed between the primary tissue-removing components around the tissue-removing blade. The tissue-removing element is made by removing material from a blank to form the primary and secondary tissue-removing components.

What is claimed is: 
     
       1. A tissue-removing catheter for removing tissue from a biological lumen, the tissue-removing catheter comprising:
 a rotatable shaft; and 
 a tissue-removing element coupled to the rotatable shaft for rotating the tissue-removing element about an axis of rotation, the tissue-removing element having opposite first and second axial ends and an exterior surface extending generally axially from the first axial end to the second axial end and extending circumferentially about the axis of rotation, the tissue-removing element comprising:
 a plurality of primary tissue-removing components at the first axial end of the tissue-removing element and spaced apart from one another around the axis of rotation, each primary tissue-removing component having a leading surface extending generally axially, a radially outer surface extending generally axially, a radially inner surface extending generally axially and generally inward relative to the axis of rotation from adjacent a leading end toward a trailing end thereof, and an axial end surface intersecting the leading, the radially outer, and the radially inner surfaces at respective leading, radially outer, and radially inner edges,
 wherein the leading surface, the leading edge and leading portions of the radially outer surface, the radially inner surface, and the axial end surface at least partially forms a cutting tooth adapted to cut tissue as the tissue-removing element rotates to facilitate removal of tissue, 
 wherein trailing portions of the radially outer surface, the radially inner surface, and the axial end surface at least partially forms an inner shearing member adapted to impact tissue and shear the impacted tissue radially inwardly as the tissue-removing element rotates to facilitate removal of hard tissue, 
 wherein the radially outer surface of each primary tissue-removing component forms a respective portion of the exterior surface of the tissue-removing element, and 
 wherein the radially outer surface of each primary tissue-removing component intersects the leading surface of the respective primary tissue-removing component at an outer axial edge extending generally axially, 
 wherein the leading surface of each primary tissue-removing component intersects the respective radially inner surface at an intermediate axial edge extending generally axially, 
 wherein the intermediate axial edge intersects the respective radially inner edge at a radially inner axial end corner of the cutting tooth, and 
 wherein the radially inner edge extends contiguously from the radially inner axial end corner of the cutting tooth to the trailing end of the radially inner surface and forms a leading axial edge of the inner shearing member located radially inward of the radially inner axial end corner of the cutting tooth. 
 
 
 
     
     
       2. The tissue-removing catheter set forth in  claim 1 , wherein the cutting tooth and the inner shearing member of each primary tissue-removing component are integrally formed as a single piece of material. 
     
     
       3. The tissue-removing catheter set forth in  claim 2 , wherein the primary tissue-removing components are integrally formed as a single piece of material. 
     
     
       4. The tissue-removing catheter set forth in  claim 1 , wherein the radially inner surface of each primary tissue-removing component has an arcuate portion curving inward relative to the axis of rotation from adjacent the leading end toward the trailing end thereof. 
     
     
       5. The tissue-removing catheter as set forth in  claim 4 , wherein the tissue-removing element has an outer surface defining a radius of the tissue-removing element, wherein the arcuate portion of the radially inner surface of at least one of the primary tissue-removing components has a radius of curvature that is from about 1% to about 50% of the radius of the tissue-removing element. 
     
     
       6. The tissue-removing catheter set forth in  claim 4 , wherein the arcuate portion of the radially inner surface of each primary tissue-removing component forms part of the inner shearing member. 
     
     
       7. The tissue-removing catheter set forth in  claim 6 , wherein the radially inner surface of each primary tissue-removing component has a transverse portion extending generally inward relative to the axis of rotation from a trailing end of the arcuate portion toward the trailing end of the radially inner surface, the transverse portion extending generally transverse to the cutting tooth. 
     
     
       8. The tissue-removing catheter as set forth in  claim 7 , wherein the tissue-removing element has an outer surface defining a radius of the tissue-removing element, wherein the transverse portion of the radially inner surface of at least one of the primary tissue-removing components has a length that is from about 1% to about 75% of the radius of the tissue-removing element. 
     
     
       9. The tissue-removing catheter as set forth in  claim 7 , wherein the transverse portion of the radially inner surface of at least one of the primary tissue-removing components extends generally in an impact plane that is offset from the axis of rotation in a direction perpendicular to the impact plane. 
     
     
       10. The tissue-removing catheter as set forth in  claim 9 , wherein the impact plane is offset from the axis of rotation in by an offset distance of about 0.010 inches (0.254 mm). 
     
     
       11. The tissue-removing catheter set forth in  claim 1 , further comprising a plurality of secondary cutting components at the first axial end of the body and spaced apart from one another around the axis of rotation, each secondary cutting component being disposed between adjacent primary tissue-removing components and having a leading surface extending generally axially, a radially outer surface extending generally axially, a radially inner surface extending generally axially and generally inward relative to the axis of rotation from adjacent a leading end toward a trailing end thereof, and an axial end surface intersecting the leading, the radially outer, and the radially inner surfaces at respective leading, radially outer, and radially inner edges,
 wherein the leading surface, the leading edge, and leading portions of the radially outer surface, the radially inner surface, and the axial end surface at least partially forms a cutting tooth adapted to cut tissue as the tissue-removing element rotates to facilitate removal of tissue. 
 
     
     
       12. The tissue-removing catheter set forth in  claim 1 , wherein the leading surface of each primary tissue-removing component defines a positive rake angle of the corresponding cutting tooth. 
     
     
       13. The tissue-removing catheter as set forth in  claim 12 , wherein the rake angle of at least one of the cutting teeth is in a range of from about +5° to about +35°. 
     
     
       14. The tissue-removing catheter set forth in  claim 1 , wherein the leading edge of each primary tissue-removing component defines a fleam angle of the cutting tooth, the fleam angle being greater than 0 degrees. 
     
     
       15. The tissue-removing catheter as set forth in  claim 14 , wherein the fleam angle of at least one of the cutting teeth is in a range of from about from about 1° to about 60°. 
     
     
       16. The tissue-removing catheter set forth in  claim 1 , wherein the axial end surface of each primary tissue-removing component has a tilt angle relative to a plane that is orthogonal to the axis of rotation, wherein the tilt angle is constant from the corresponding cutting tooth to the corresponding inner shearing member of the primary tissue-removing component. 
     
     
       17. The tissue-removing catheter as set forth in  claim 1 , wherein the tissue-removing element has an outer surface defining a radius of the tissue-removing element, and the inner shearing member of at least one of the primary tissue-removing components has a radially innermost point with respect to the axis of rotation, wherein said shearing member has a radial length that extends from the radially innermost point to the outer surface of the tissue-removing element along an imaginary line that passes through both the axis of rotation and the innermost point in a plane perpendicular to the axis of rotation, wherein the radial length is less than the radius of the tissue-removing element. 
     
     
       18. The tissue-removing catheter as set forth in  claim 17 , wherein the radial length is from about 10% to about 80% of the radius of the tissue-removing element.